Measuring distances¶

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Distances can be computed between trajectories as well as between trajectories and other geometry objects. The implemented distance measures are:

  • Shortest distance
  • Hausdorff distance
In [1]:
import pandas as pd
import geopandas as gpd
import movingpandas as mpd
import shapely as shp
import hvplot.pandas 
import matplotlib.pyplot as plt

from geopandas import GeoDataFrame, read_file
from shapely.geometry import Point, LineString, Polygon
from datetime import datetime, timedelta
from holoviews import opts, dim

import warnings
warnings.filterwarnings('ignore')

plot_defaults = {'linewidth':5, 'capstyle':'round', 'figsize':(9,3), 'legend':True}
opts.defaults(opts.Overlay(active_tools=['wheel_zoom']))
hvplot_defaults = {'tiles':'CartoLight', 'frame_height':320, 'frame_width':320, 'cmap':'Viridis', 'colorbar':True}

mpd.show_versions()

MovingPandas 0.16.0

SYSTEM INFO
-----------
python     : 3.10.8 | packaged by conda-forge | (main, Nov 22 2022, 08:16:53) [MSC v.1929 64 bit (AMD64)]
executable : H:\miniconda3\envs\mpd-ex\python.exe
machine    : Windows-10-10.0.19045-SP0

GEOS, GDAL, PROJ INFO
---------------------
GEOS       : None
GEOS lib   : None
GDAL       : 3.5.0
GDAL data dir: None
PROJ       : 9.0.0
PROJ data dir: H:\miniconda3\pkgs\proj-9.0.0-h1cfcee9_1\Library\share\proj

PYTHON DEPENDENCIES
-------------------
geopandas  : 0.13.0
pandas     : 2.0.1
fiona      : 1.8.21
numpy      : 1.23.5
shapely    : 1.8.2
rtree      : 1.0.1
pyproj     : 3.3.1
matplotlib : 3.7.1
mapclassify: 2.4.3
geopy      : 2.3.0
holoviews  : 1.14.9
hvplot     : 0.8.3
geoviews   : 1.9.6
stonesoup  : 0.1b12

Measuring distances between trajectories¶

In [2]:
df = pd.DataFrame([
  {'geometry':Point(0,0), 't':datetime(2018,1,1,12,0,0)},
  {'geometry':Point(6,0), 't':datetime(2018,1,1,12,6,0)},
  {'geometry':Point(6,6), 't':datetime(2018,1,1,12,10,0)},
  {'geometry':Point(9,9), 't':datetime(2018,1,1,12,15,0)}
]).set_index('t')
geo_df = GeoDataFrame(df, crs=31256)
toy_traj = mpd.Trajectory(geo_df, 1)
toy_traj.df
Out[2]:
geometry
t
2018-01-01 12:00:00 POINT (0.000 0.000)
2018-01-01 12:06:00 POINT (6.000 0.000)
2018-01-01 12:10:00 POINT (6.000 6.000)
2018-01-01 12:15:00 POINT (9.000 9.000)
In [3]:
df = pd.DataFrame([
  {'geometry':Point(3,3), 't':datetime(2018,1,1,12,0,0)},
  {'geometry':Point(3,9), 't':datetime(2018,1,1,12,6,0)},
  {'geometry':Point(2,9), 't':datetime(2018,1,1,12,10,0)},
  {'geometry':Point(0,7), 't':datetime(2018,1,1,12,15,0)}
]).set_index('t')
geo_df = GeoDataFrame(df, crs=31256)
toy_traj2 = mpd.Trajectory(geo_df, 1)
toy_traj2.df

ax = toy_traj.plot()
toy_traj2.plot(ax=ax, color='red')
Out[3]:
<Axes: >
In [4]:
print(f'Distance: {toy_traj.distance(toy_traj2)} meters')
print(f'Hausdorff distance: {toy_traj.hausdorff_distance(toy_traj2):.2f} meters')

Distance: 3.0 meters
Hausdorff distance: 6.08 meters
In [5]:
print(f'Distance: {toy_traj.distance(toy_traj2, units="cm")} cm')
print(f'Hausdorff distance: {toy_traj.hausdorff_distance(toy_traj2, units="km"):.6f} km')

Distance: 300.0 cm
Hausdorff distance: 0.006083 km

Measuring distances between trajectories and other geometry objects¶

In [6]:
pt = Point(1, 5)
line = LineString([(3,3), (3,9)])
pt_gdf = GeoDataFrame(pd.DataFrame([{'geometry':pt, 'id':1}]))
line_gdf = GeoDataFrame(pd.DataFrame([{'geometry':line, 'id':1}]))

ax = toy_traj.plot()
pt_gdf.plot(ax=ax, color='red')
line_gdf.plot(ax=ax, color='red')
Out[6]:
<Axes: >
In [7]:
print(f'Distance: {toy_traj.distance(pt)}')
print(f'Hausdorff distance: {toy_traj.hausdorff_distance(pt):.2f}')

Distance: 5.0
Hausdorff distance: 8.94
In [8]:
print(f'Distance: {toy_traj.distance(line)}')
print(f'Hausdorff distance: {toy_traj.hausdorff_distance(line)}')

Distance: 3.0
Hausdorff distance: 6.0
In [9]:
print(f'Distance: {toy_traj.distance(line, units="cm")} cm')
print(f'Hausdorff distance: {toy_traj.hausdorff_distance(line, units="km"):.6f} km')

Distance: 300.0 cm
Hausdorff distance: 0.006000 km
In [ ]: